216

192 = 11000000

224 = 11100000

Apply the host calculation formula:

2⁵ – 2 = 30 hosts per subnet

Subnetting: Dividing Networks into Right Sizes

Every network within the internetwork of a corporation or organization is designed to accommodate a finite number of hosts. Some networks, such as point-to-point WAN links, only require a maximum of two hosts. Other networks, such as a user LAN in a large build-ing or department, might need to accommodate hundreds of hosts. Network administrators need to devise the internetwork addressing scheme to accommodate the maximum number of hosts for each network. The number of hosts in each division should allow growth in the number of hosts.

To examine this process, see the example network in Figure 6-21. Each step of this process in the following sections will use this as an example. Subnetting an address block for an internetwork uses the following steps:

How To

Step 1.      Determine the total number of addresses.

Step 2.      Determine the number of networks and the number of hosts in each network.

Step 3.      Partition the address block to create a network of appropriate size for the largest subnet network.

Step 4.      Create another partition of appropriate size for the next largest network.

Step 5.      Continue to create partitions for each subsequently smaller network until all sub-nets have address blocks assigned.

Determine the Total Number of Hosts

First, consider the total number of hosts required by the entire corporate internetwork. You must use a block of addresses that is large enough to accommodate all devices in all the corporate networks. This includes end-user devices, servers, intermediate devices, and router interfaces.